702 / 2022-03-31 16:31:16

Design and Development of LV/MV DC Liquid Metal Fault Current Limiter

Fault current limiter,Arc,Liquid Metal

Purpose/Aim

With the deepening interconnection and increasing capacity of DC power systems, fault current limitation becomes a more and more prominent challenge. The liquid metal fault current limiter (LMFCL) is a promising device to limit DC faults, but suffers a dilemma between normal current carrying capacity and fault current limiting capability. In this work, two LMFCL topologies based on current commutation methods are presented to overcome the dilemma successfully.

Experimental/Modeling methods

The two LMFCL topologies are presented along with their detailed working principles. Then the simulations are conducted to determine the optimized design parameters of key components, and full-scale LV/MV LMFCL prototypes are both developed. Finally, large capacity tests are conducted to validate the normal current carrying and fault current limiting performances.

Results/discussion

The LMFCL prototypes are able to carry several kilo-amperes current with very low conduction loss under normal condition, and can limit prospective current up to 100 kA to several kilo-amperes in 1.5ms when a fault occurs. The advantages of the proposed LMFCLs are their fast response, outstanding capacity of high nominal current-carrying and large fault current.

Conclusions

The results demonstrates that the proposed LMFCLs have the potential to be used in DC power systems. Compared with other kinds of FCLs, cooling systems are not needed under normal condition. The operation loss is very low, while the fault limiting capacity is very high. The LMFCL prototypes are developed for LV/MV DC power systems, and more work will focus on the increase of its voltage rating in the future.